An orthographic projection is a technique used in technical drawing and engineering to represent a three-dimensional object in two dimensions. It provides a series of flat, two-dimensional views of an object from different perspectives. These views, called orthographic views, show the object as if it has been projected onto an imaginary box with planes that are perpendicular to each other.

In an orthographic projection, the object is typically shown in three main views: front view, top view, and side view. The front view represents the object as it would appear when looking directly at its front face. The top view shows the object as if looking down from above, and the side view displays the object from the side.

Each view provides specific information about the object's dimensions, shape, and features. By combining these different views, viewers can understand the object's complete geometry and how its various parts relate to each other in a detailed and precise manner.

Orthographic projections follow specific conventions and use standard symbols and lines to represent various features such as edges, surfaces, and hidden lines. These projections are widely used in fields like engineering, architecture, manufacturing, and design, where accurate and clear representation of objects is crucial for communication and construction purposes.

Multiview Drawings

Another name for an orthographic projection is a multiview drawing. The standard three views of a multiview drawing are front, right side, and top view. These are the views drawn in an orthographic projection because a person looking at the drawing can see all the important aspects of that drawing needing only these views. The best way to think about how to get these views from a 3D object is to imagine the object in a glass box. 

Glass Box Theory

Imagine that the object is inside a glass box and we are drawing the surfaces projected onto the glass box. If you were to open the box and unfold it, what you would see projected is the 2D views. 

Once the box is unfolded you will have multiple 2D representations of your 3D object. These views are labeled based on the orientation you are looking at the object. Generally speaking the front view is the view that contains the most information on the object and from there you can assign the other views. The right and left side views are to the right and left of the front view. The top and bottom are you guessed it, the top and bottom based off of the front view and the back view is the view behind the front view. 

In general though the only three views that are used is the front, top and right side because the other views only repeat the information given in those three. There are times when only two views are required because you can convey all the information with only those two views but in general we will be working with the standard three view drawing when talking about orthographic projections. 

Practice Problems - Orthographic Projections

Look at each object's 3D isometric view and try to find which orthographic projection represents the object. There is only one correct answer for each object. Pay careful attention to what would be a hidden line based on the orientation you are looking at the object.  


Practice Orthographic projection problem - 1


Practice Orthographic projection problem - 2


Practice Orthographic projection problem - 3


Practice Orthographic projection problem - 4


Practice Orthographic projection problem - 5


Practice Orthographic projection problem - 6


Practice Orthographic projection problem - 7


Practice Orthographic projection problem - 8


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Hand drafting an orthographic projection involves creating a two-dimensional representation of a three-dimensional object using a set of standard drawing techniques. Orthographic projection is a method of representing objects in a way that shows their true shape and size without distortion. Here are some basic steps to hand drafting an orthographic projection:

Remember, hand drafting an orthographic projection requires practice and attention to detail. Take your time, use the appropriate tools, and refer to drafting standards and conventions to ensure your drawing is clear and precise. Anyone should be able to pick up your drawing and be able to produce what you drew. 

Drawing 1: ANVIL

A good drawing to start hand drafting orthographic projections. The only thing you should be aware of is reproducing the angled faces. When looking at them from the top and side view you will see them as straight object lines. Which is why you draw more than one view since some information is lost if you do not show all pertiniant sides of an object. 

Example practice orthographic projection problem - Anvil

Step 1

Find the center of your paper to see where you should place your views

Step 2

Draw the front view with the side of the view in line with the center mark and at least an inch from the title block to leave room for dimensions

Step 3

Draw the construction lines that you will need to transfer the important features from the front view to the other views. Notice I have included the 45 degree angled transfer line to transfer things from the top view to the side.

Step 4

Draw in the object lines for the top and side view. Make sure the spacing is equal with the front view and that they line up with each other. The space will be used for dimensioning the drawing.

Step 5

Step 6

Clean up the drawing and add dimensions.


Example practice orthographic projection problem - Slide

Drawing 2: SLIDE

The angle on the front face is not given but there is enough information given to be able to draw all the views. You will need the angled transfer line to transfer the location of the angled face from the side view to the top view.

Example practice orthographic projection problem - Finger Lock

Drawing 3: LOCK FINGER

First drawing with circles and arcs. Remeber a circle from the side is just a rectangle. Be sure to follow demsioning rules and only give a diameter or radius dimension from the face where it is visible and not to the hidden lines. 

Example practice orthographic projection problem - Bearing

Drawing 4: BEARING

The front view is missing but there is enough information given to be able to produce the front view for your drawing. Other than that a straight forwards drawing.

In case you were wondering, the answers to the practice problems are : BEH, FJK, ILD, CGA